Percent Fall In FEV1 Research Articles

Cut-off value for exercise-induced bronchoconstriction based on the features of the airway obstruction.

The current cut-off value for diagnosing exercise-induced bronchoconstriction (EIB) in adults—percent fall in FEV1 (ΔFEV1) ≥ 10% after exercise challenge test (ECT)—has low specificity and weak evidences. Therefore, this study aimed to identify the cut-off value for EIB that provides the highest diagnostic sensitivity and specificity. Participants who underwent the ECT between 2007 and 2018 were categorized according to ΔFEV1: definite EIB (ΔFEV1 ≥ 15%), borderline (10% ≤ ΔFEV1 < 15%), and normal (ΔFEV1 < 10%). Distinct characteristics of the definite EIB group were identified and explored in the borderline EIB group. A receiver operating characteristic curve was plotted to determine the optimal cut-off value. Of 128 patients, 60 were grouped as the definite EIB group, 23 as the borderline group, and 45 as the normal group. All participants were men, with a median age of 20 years (interquartile range [IQR:] 19–23 years). The definite EIB group exhibited wheezing on auscultation (P < 0.001), ΔFEV1/FVC ≥ 10% (P < 0.001), and ΔFEF25–75% ≥ 25% (P < 0.001) compared to other groups. Eight (8/23, 34.8%) patients in the borderline group had at least one of these features, but the trend was more similar to that of the normal group than the definite EIB group. A cut-off value of ΔFEV1 ≥ 13.5% had a sensitivity of 98.5% and specificity of 93.5% for EIB. Wheezing on auscultation, ΔFEV1/FVC ≥ 10%, and ΔFEF25–75% ≥ 25% after ECT may be useful for the diagnosis of EIB, particularly in individuals with a ΔFEV1 of 10–15%. For EIB, a higher cut-off value, possibly ΔFEV1 ≥ 13.5%, should be considered as the diagnostic criterion.

Albuterol/budesonide for the treatment of exercise-induced bronchoconstriction in patients with asthma: The TYREE study

BackgroundPT027 is a fixed-dose combination of albuterol (salbutamol) and budesonide in a single pressurized metered-dose inhaler. ObjectiveTo evaluate the efficacy and safety of albuterol/budesonide compared with placebo in patients with asthma and exercise-induced bronchoconstriction (EIB). MethodsIn this randomized, double-blind, 2-period, single-dose crossover study, adolescents and adults with asthma and EIB (defined by ≥20% decrease from pre-exercise challenge forced expiratory volume in 1 second [FEV1]) were randomized to albuterol/budesonide (180/160 µg) followed by placebo (n = 29) or the reverse sequence (n = 31). Subjects were stratified by background therapy (as-needed short-acting β2-agonist alone or low-to-medium dose inhaled corticosteroid plus as-needed short-acting β2-agonist). FEV1 was measured 5 minutes pre-dose, 30 minutes postdose (5 minutes pre-exercise challenge [baseline]), and 5, 10, 15, 30, and 60 minutes postexercise. The primary end point was maximum percentage fall from baseline in FEV1 up to 60 minutes postexercise challenge. ResultsLeast squares mean maximum percentage fall in FEV1 up to 60 minutes postexercise challenge was 5.45% with albuterol/budesonide vs 18.97% with placebo (difference, −13.51% [95% confidence interval, −16.94% to −10.09%]; P < .001). More subjects were fully protected (maximum percentage fall in FEV1 post-exercise challenge < 10%) with albuterol/budesonide than with placebo (78.3% vs 28.3%; P < .001). The treatment effect was consistent irrespective of background inhaled corticosteroid therapy, and albuterol/budesonide was well tolerated. ConclusionIn adolescents and adults with asthma and EIB, a single dose of albuterol/budesonide 180/160 µg taken approximately 30 minutes before exercise was significantly more effective than placebo in preventing EIB. Trial RegistrationClinicalTrials.gov Identifier: NCT04234464

Exercise-induced bronchoconstriction and bronchodilation: investigating the effects of age, sex, airflow limitation and FEV1.

Exercise-induced bronchoconstriction (EIBc) is a recognised response to exercise in asthmatic subjects and athletes but is less well understood in an unselected broad population. Exercise-induced bronchodilation (EIBd) has received even less attention. The objective of this study was to investigate the effects of age, sex, forced expiratory volume in 1 s (FEV1) and airflow limitation (FEV1/forced vital capacity (FVC) <0.7) on the prevalence of EIBc and EIBd.This was a retrospective study based on incremental cardiopulmonary exercise testing on cycle ergometry to symptom limitation performed between 1988 and 2012. FEV1 was measured before and 10 min after exercise. EIBc was defined as a percentage fall in FEV1 post-exercise below the 5th percentile, while EIBd was defined as a percentage increase in FEV1 above the 95th percentile.35 258 subjects aged 6-95 years were included in the study (mean age 53 years, 60% male) and 10.3% had airflow limitation (FEV1/FVC <0.7). The lowest 5% of subjects demonstrated a ≥7.6% fall in FEV1 post-exercise (EIBc), while the highest 5% demonstrated a >11% increase in FEV1 post-exercise (EIBd). The probability of both EIBc and EIBd increased with age and was highest in females across all ages (OR 1.76, 95% CI 1.60-1.94; p<0.0001). The probability of EIBc increased as FEV1 % pred declined (<40%: OR 4.38, 95% CI 3.04-6.31; p<0.0001), with a >2-fold increased likelihood in females (OR 2.31, 95% CI 1.71-3.11; p<0.0001), with a trend with airflow limitation (p=0.06). The probability of EIBd increased as FEV1 % pred declined, in the presence of airflow limitation (OR 1.55, 95% CI 1.24-1.95; p=0.0001), but sex had no effect.EIBc and EIBd can be demonstrated at the population level, and are influenced by age, sex, FEV1 % pred and airflow limitation.

Prevalence of Exercise Induced Bronchoconstriction in Recreational Adult Hockey Players as determined by Sport Specific Field Exercise Challenge Test

BACKGROUND: Exercise induced bronchoconstriction (EIB) is provoked by exercise and results in narrowing of the airways. Studies have shown an EIB prevalence of 11-50% in athletic populations. The diagnosis of EIB is dependent upon objective measurement of respiratory function, as respiratory symptoms are unreliable. Cold and dry ambient conditions contribute to the severity of EIB. The environmental conditions and manner of exertion an athlete is exposed to in ice hockey are significantly different than any current standardized laboratory test to evaluate for EIB. In a prior study of elite women hockey players, 39.5% presented symptoms of asthma and 21% demonstrated EIB. Sport-specific field exercise challenge tests (SSFECT) have been validated for the assessment of EIB, and are more sensitive than laboratory challenges in elite winter athletes. PURPOSE: To use a SSFECT to determine the prevalence of EIB in adult recreational ice hockey players, and the correlation between reported symptoms and diagnosis by this method. METHODS: Participants were 18 males and 2 females (mean age of 34.7 yrs, mean height of 1.78 m); who participated in 1 of 2 recreational ice hockey leagues in Chicago, IL. Using a Piko-1 portable spirometer, FEV1 was measured prior to the hockey game and immediately following periods 1, 2, and 3. All respiratory measurements occurred with hockey equipment adorned. Airway response was expressed as the percent fall in FEV1 from the baseline value. Diagnosis of EIB was given if athletes had a greater than 10% decrease in FEV1 from baseline measured at any time point. Athletes also completed an intake questionnaire prior to testing which included clinical symptoms, exercise history, and past medical history. RESULTS: EIB was diagnosed in 3/20(15%) athletes. A prior diagnosis of asthma or exercise induced asthma was reported in 5/20 (25%) athletes, yet only one of these had a decrease of > 10 % of FEV1 as measured by this test. Of the three EIB+, two were symptomatic (67%); and of the EIB-, 9/17 (53%) reported respiratory symptoms. Diagnosis of EIB was consistent for all three periods in all but one athlete. Mean FEV1 for the three periods was 4.08, 4.07, and 4.07 respectively. CONCLUSIONS: Symptoms remain unreliable for diagnosis of EIB. SSFECT can be utilized for diagnosis of EIB in ice hockey athletes.

Exercise-induced Bronchoconstriction with Firefighting Contained Breathing Apparatus.

Protective self-contained breathing apparatus (SCBA) used for firefighting delivers decompressed (cold) dehumidified air that may enhance the severity of exercise-induced bronchoconstriction (EIB) in those susceptible. We investigated the effect of SCBA during exercise on airway caliber in people with asthma and healthy controls. Two exercise challenges (EC) designed to elicit EIB were performed on separate days within 1 wk. The initial challenge was breathing room air (ECRA) with workload titrated to elicit >60% estimated maximum voluntary ventilation. The exercise intensity was repeated for the second challenge using SCBA (ECSCBA). Forced expiratory volume in 1 s (FEV1) was measured before and up to 20 min after exercise. Bronchial hyperresponsivenss (BHR) to the hyperosmolar mannitol test was measured in the subjects with asthma. Twenty subjects with current asthma (mean [SD]: age 27 [6] yr) and 10 healthy controls (31 [5] yr, P = 0.1) were studied. The percent fall in FEV1 after ECSCBA was greater in the mannitol-positive asthma subjects (14.4% [15.1%]) compared with mannitol-negative asthmatic subjects (1.6% [1.7%]; P = 0.02) and controls (2.3% [2.3%]; P = 0.04). The FEV1 response was not different between ECRA and ECSCBA (0.49% [5.57%]; P = 0.6). No BHR to mannitol (n = 7) was highly sensitive for identifying a negative response to ECSCBA (negative predictive value 100%). The SCBA does not increase the propensity or severity for EIB in subjects with BHR. Those subjects with asthma but no BHR to inhaled mannitol did not exhibit EIB. The BHR to a hyperosmolar stimulus maybe considered a useful screening tool for potential recruits with a history of asthma.

Time-Effect of Formoterol Added to Inhaled Fluticasone on Exercise- Induced Bronchoconstriction in Asthmatic Adolescents

Background: Asthma is characterized by chronic airway inflammation that is controlled by a complex cytokine network. Inhaled corticosteroid and short acting β2-agonists treatment improve asthma control. Objective: The aim of the study is to evaluate if a combination of fluticasone and formoterol is effective to assure a protective effect against EIB 15 min and 4 hours after administration in adolescent with persistent asthma. Method: In this study we selected 20 adolescents age 8 and 19 years affected by mild to moderate persistent asthma and EIB. At screening the following were assessed: eligibility, demography, medical history, medications, spirometry and clinical examination. During the study all the patients continued to regularly take a low dose of inhaled steroids; albuterol as rescue medication has been discontinued 8 hours before the exercise test. Results: Formoterol plus fluticasone offered good protection against EIB in 18 patients (90%), the mean maximum percent fall in FEV1 after formoterol was 7.1 ± 4.9% at 15 min (p<0.001). The combination formoterol plus fluticasone was more effective after 4 hours protecting against bronchoconstriction 19 patients (95%) and the mean maximum percent fall in FEV1 after formoterol plus fluticasone was 4.3 ± 4.2% at 4 h (p < 0.001). Conclusions: This study suggests that fluticasone 100 mcg + formoterol 10mcg by MDI + spacer is effective in protecting asthmatic adolescents as early as 15 min after dosing. Furthermore, the data confirm the long duration of its protective effect and the absence of any significant adverse effects after administration. Keywords: Children, exercise-induced bronchoconstriction, fluticasone, formoterol, physical activity.

THE PROTECTIVE EFFECTS OF VARIOUS WARM-UP MODALITIES ON EXERCISE-INDUCED BRONCHOSPASM (EIB) IN NON-ASTHMATIC ATHLETES

BackgroundExercise-induced bronchospasm (EIB) that is a transient airway obstruction occurring after strenuous exertion can occur in non-asthmatic athletes as well. However acute effects of different warm-up modalities on EIB in...

The success and safety profile of sputum induction in patients with chronic obstructive pulmonary disease: An Indian experience

BackgroundNeutrophilic inflammation is common in chronic obstructive pulmonary disease while Asthma COPD overlap syndrome has eosinophilic predominance. Identifying the type of inflammation will aid in better management of COPD, but published studies show that induced sputum examination is more frequently used in asthma than COPD, with safety being the limiting factor. We aimed to determine the success and safety of sputum induction (SI) in COPD patients. Methods116 stable COPD patients underwent SI. Success was defined as adequate sputum sample resulting in a cytospin sufficient to assess differential count while safety by the fall in FEV1. ResultsThe mean (SD) FEV1% predicted post bronchodilator was 58.8 (17.8) and 59 (51.8%) patients had moderate COPD. Success was 98.28%. The procedure was safe with overall fall in FEV1 of 11.1% (5.1, 15.2). ≥20% fall was noted in 13 (11.4%) patients, 10–20% in 24 (21.0%) patients, and less than 10% in 29 (25.4%) patients while 48 (42.1%) had no fall. There was an inverse correlation between reversibility in FEV1 and percentage fall in FEV1; r=−0.437 and p=0.001. Stepwise multivariate linear regression showed reversibility as an independent predictor of fall in FEV1; R2=0.137. ConclusionsSputum induction is successful and safe in COPD. Even a fall in FEV1>20% is reversible.

Asthma Control Test and Bronchial Challenge with Exercise in Pediatric Asthma.

Poor asthma control can lead to exercise-induced bronchoconstriction (EIB), but the relationship between subjective disease control and EIB is unclear. No studies have compared asthma control test (ACT) scores of children with those of their parents regarding EIB. We assessed whether ACT scores predict the occurrence of EIB in two age groups. We also evaluated ACT scores and objective measures as explanatory variables for airway response to exercise. Patients (71, aged <12 years; 93, aged ≥12 years) and their parents completed an ACT questionnaire separately. Current therapy, skin prick testing, and spirometry at baseline and after exercise were assessed. EIB was defined as a fall in forced expiratory volume in 1 s (FEV1) of at least 12% from baseline. Sensitivity and specificity for cut-off values of ACT scores predictive of EIB were plotted, and the area under curve (AUC) was described. Atopy and current therapy were similarly frequent. EIB was observed in 23.9% of children aged <12 years and in 33.3% of children aged ≥12 years. EIB occurrence in subjects previously scored as having full control (25), partial control (20-24), and no control (<20) varied according to the age group and responders. Percentages of EIB cases increased as ACT scores decreased in children aged ≥12 years alone (child ACT scores, 25: 21.9%, 20-24: 31.1%, <20: 62.5%, p = 0.017). Plots for ACT scores as predictors of EIB yielded low non-significant AUC values in children aged <12 years; in contrast, moderate AUC values emerged in children aged ≥12 years (child: 0.67, p = 0.007; parent: 0.69, p = 0.002). Sensitivity of ACT scores below 20 as a predictor of EIB was low in older children (child: 32.3%, parent: 22.6%), whereas specificity was high (child: 90.3%, parent: 93.5%). Multiple regression analysis with percent fall in FEV1 as dependent variable included FEV1/FVC%, ACT child score, and gender in the prediction model (r = 0.42, p = 0.000). ACT scores are a more effective means of excluding than confirming EIB in asthmatic patients aged ≥12 years; their predictive value decreases in younger patients. ACT scores together with lung function may help to predict airway response to exercise. New tools for pediatric asthma assessment may optimize this association.

Novel albuterol multidose dry powder inhaler in patients with exercise-induced bronchoconstriction: A single-dose, double-blind, randomized, 2-way crossover study

BackgroundA novel, inhalation-driven, multidose dry powder inhaler (MDPI) was developed that eliminates the need to coordinate device actuation with inhalation as is required with conventional metered-dose inhalers. ObjectiveTo evaluate albuterol MDPI efficacy and safety in patients with exercise-induced bronchoconstriction (EIB). MethodsThis single-dose, double-blind, 2-way crossover study randomized adolescents and adults with EIB (≥20% fall from pre-exercise challenge FEV1) to treatment sequences of albuterol MDPI (180 μg [2 inhalations of 90 μg each])/placebo MDPI (n = 19) or the reverse sequence (n = 19). FEV1 was measured 30 and 5 min predose, 30 min postdose (ie, 5 min before treadmill exercise challenge; baseline) and 5, 10, 15, 30, and 60 min after exercise challenge. The primary efficacy endpoint was maximum percentage fall from baseline in FEV1 up to 60 min post-exercise challenge. ResultsMean maximum percentage fall in FEV1 within 60 min post-exercise challenge was 6.2 ± 1.4% for albuterol MDPI versus 22.4 ± 1.4% for placebo MDPI (between-treatment difference: −16.2%; 95% CI: −20.2% to −12.1%; P < 0.0001). A significantly higher percentage of albuterol MDPI–treated patients were protected against EIB (<10% maximum FEV1 fall post-exercise challenge) versus placebo MDPI (84.2% vs 15.8%; P < 0.0001). Protection with albuterol MDPI was evident within 5 min and maintained through 30 min; recovery was complete for both groups at 60 min. Treatment with a single dose of albuterol MDPI was generally well tolerated. ConclusionsAlbuterol MDPI provides clinically significant protection from EIB in adolescents and adults with EIB; no new safety issues were observed with short-term albuterol MDPI use. ClinicalTrials.gov identifier NCT01791972.

Onset and duration of attenuation of exercise-induced bronchoconstriction in children by single-dose of montelukast

Single-dose montelukast attenuates exercise-induced bronchoconstriction (EIB) in adults within 2 hours postdose and lasting through 24 hours. This study evaluated the onset and duration of EIB attenuation in children after a single dose of montelukast. A randomized, double-blind, placebo-controlled, two-period crossover study was performed. Patients (n = 66) aged 4-14 years, with preexercise forced expiratory volume in 1 second of (FEV(1)) ≥70% predicted and maximum percentage fall in FEV(1) of ≥20% at two screening exercise challenges were eligible. Patients were to receive single-dose montelukast (4 or 5 mg) or placebo before performing standardized exercise challenges at 2 and 24 hours postdose. A 3- to-7-day washout separated the two crossover periods. The primary end point was maximum percentage fall in FEV(1) after exercise challenge 2 hours postdose. Secondary end points included maximum percentage fall in FEV(1) after the 24-hour postdose challenge; each of the following at 2 and 24 hours postdose-maximum percentage fall in FEV(1) categorized as <10%, 10-20%, or >20%; area under the curve (AUC) during 60 minutes postchallenge; time to recovery of FEV(1) to within 5% of preexercise baseline; and need for rescue medication. The mean maximum percentage fall in FEV(1) after the 2-hour postdose exercise challenge was significantly attenuated after single-dose montelukast compared with placebo (15.35% versus 20.00%; p = 0.020). Montelukast was also significantly more effective than placebo for maximum percentage fall after the 24-hour challenge (12.92% versus 17.25%; p = 0.005), the categorized maximum percent fall in FEV(1) at 2 hours (p = 0.034), and AUC at 2 hours (p = 0.022) and 24 hours (p = 0.013). Single-dose montelukast provided rapid and sustained EIB attenuation in children. Clinicaltrials.gov identifier: NCT00534976.

Predictors of Airway Hyperresponsiveness Differ Between Old and Young Patients With Asthma

Age-related increases in morbidity and mortality due to asthma may be due to changes in pathophysiology as patients with asthma get older. There is limited knowledge about the effects of age on the predictors of airway hyperresponsiveness (AHR), a key feature of asthma. The aim of this study was to determine if the pathophysiologic predictors of AHR, including inflammation, ventilation heterogeneity, and airway closure, differed between young and old patients with asthma. Sixty-one young (18-46 years) and 43 old (50-80 years) patients with asthma had lung function, lung volumes, fraction of exhaled nitric oxide, ventilation heterogeneity, and airway responsiveness to methacholine measured. Airway response to methacholine was measured by the dose-response slope, as the percent fall in FEV(1) per micromole of methacholine. Indices of ventilation heterogeneity were calculated for convection-dependent and diffusion-dependent airways. In young patients with asthma, the independent predictors of AHR were convection-dependent ventilation heterogeneity, exhaled nitric oxide, and % predicted FEV(1)/FVC (model r(2) = 0.51, P < .0001). In old patients with asthma, the independent predictors of airway responsiveness were % predicted residual volume, diffusion-dependent ventilation heterogeneity, and % predicted FEV(1) (model r(2) = 0.57, P < .0001). In old patients with asthma, AHR is predicted by gas trapping and ventilation heterogeneity in peripheral, diffusion-dependent airways. In the young, it is predicted by ventilation heterogeneity in less peripheral conducting airways and by inflammation. These findings suggest that there are differences in the pathophysiologic determinants of AHR between young and old patients with asthma.

P22 Factors associated with refractoriness to repeat exercise challenge in adults with asthma

IntroductionA proportion of patients with asthma develops a refractory period, during which the bronchoconstrictor response to a second indirect challenge is reduced. A better understanding of factors associated with the...

Effects of Interleukin-13 Blockade on Allergen-induced Airway Responses in Mild Atopic Asthma

Extensive evidence in animal models supports a role for IL-13 in the pathobiology of asthma. IMA-638 and IMA-026 are fully humanized IgG(1) antibodies that bind to different epitopes and neutralize IL-13 bioactivity. We hypothesized that anti-IL-13 treatment would inhibit allergen-induced late-phase asthmatic responses, airway hyperresponsiveness, and inflammation in subjects with asthma. Fifty-six subjects with mild, atopic asthma were recruited for two double-blind, randomized, placebo-controlled, parallel group trials to compare IMA-638 and IMA-026 IL-13 antibody treatments with placebo treatment. Drug was administered on Days 1 and 8, and allergen challenges were performed on Days 14 and 35. The primary outcome variable was the late-phase area under the curve (AUC), and secondary outcome variables were the early- and late-phase maximum percent fall in FEV(1), early AUC, allergen-induced shift in airway hyperresponsiveness, and sputum eosinophils. The treatment difference with IMA-638 on Day 14 was -19.1 FEV(1) × hour (95% confidence interval: -36.2, -1.9) for the allergen-induced early AUC and -23.8 FEV(1) × hour (95% confidence interval: -46.4, -1.2) for the late AUC (both P < 0.05), but this effect was lost by Day 35. Treatment with IMA-026 did not attenuate the asthmatic responses on Day 14 or Day 35. There was no effect of either antibody on allergen-induced airway hyperresponsiveness or sputum eosinophils. The frequency of adverse events after administration of the IL-13 antibodies was similar to placebo. IL-13 has a role in allergen-induced airway responses in humans. Further study is required to determine whether anti-IL-13 monoclonal antibodies will be beneficial clinically.

Desempenho de uma escala analógica visual legendada na determinação do grau de dispneia durante teste de broncoespasmo induzido por exercício em crianças e adolescentes asmáticos

There is an indirect relationship between airway obstruction in asthma and the intensity of breathlessness (dyspnea). A word labeled visual analog dyspnea scale with a 0-3 score has been widely used for the assessment of the degree of bronchoconstriction, although the perception of such obstruction varies considerably. The objective of this study was to determine whether children and adolescents are able to perceive acute exercise-induced bronchoconstriction (EIB), as well as to measure the discriminatory power of a word labeled visual analog dyspnea scale in relation to the intensity of the EIB. A cross-sectional study involving 134 children and adolescents with asthma and submitted to a six-minute steady-state exercise test on a cycle ergometer. The intensity of dyspnea was determined using a word labeled visual analog dyspnea scale prior to each determination of FEV1. The scale is scored from 0 to 3, with a logical sequence of pictures, ranging from "no symptoms" to "severe dyspnea". Variables were determined at baseline, as well as at 5, 10, and 20 min after the exercise test. The accuracy of the dyspnea scale in identifying the degree of EIB was determined by means of ROC curves for the post-exercise fall in FEV1, using cut-off points of 10%, 20%, 30%, and 40%. Of the patients selected, 111 finished the study, and 52 (46.8%) presented with EIB. The area under the ROC curve increased in direct proportion to increases in the degree of bronchoconstriction. Among children and adolescents with asthma, the accuracy of this dyspnea scale improves as the post-exercise percentage fall in FEV1 increases. However, the predictive value of the scale is suboptimal when the percentage fall in FEV1 is lower.

Baixo grau de percepção da dispneia após teste de broncoprovocação induzida por metacolina em pacientes com asma

To determine the proportion of asthma patients with a poor perception of dyspnea, correlating the level of that perception with the severity of acute bronchoconstriction, bronchial hyperresponsiveness, use of maintenance medication, and asthma control. Uncontrolled clinical trial involving asthma patients treated at the Pulmonology Outpatient Clinic of the São Lucas Hospital, in Porto Alegre , Brazil. Methacholine challenge testing was performed using a five-breath dosimeter protocol. The perception of dyspnea after each breath was determined using the Borg scale. Data concerning asthma control, medication in use, and use of rescue short-acting bronchodilators were recorded. Of the 65 patients included in the study, 53 completed the evaluation. Of those, 32 (60.5%) showed adequate perception of dyspnea after the methacholine challenge test, whereas 21 (39.5%) did not perceive any changes in the degree of dyspnea even after a 20% fall in FEV1. There were no significant differences between the two groups regarding baseline FEV1, percentage fall in FEV1, and the dose of methacholine causing a 20% fall in FEV1. The perception of dyspnea was not significantly associated with age (p = 0.247); gender (p = 0.329); use of maintenance medication (p = 0.152); asthma control (p = 0.562), bronchial hyperresponsiveness (p = 0.082); or severity of acute bronchoconstriction (p = 0.749). A significant proportion of asthma patients have a poor perception of dyspnea. The factors related to the inability of these patients to identify changes in pulmonary function have not yet been well defined. In order to reduce asthma-related morbidity and mortality, it is essential that this group of patients be identified and counseled.

Pilot study: The effect of reducing treatment on exercise induced bronchoconstriction

SUMMARY RATIONALE: Asthma therapy should be stepped up or stepped down in response to changes in asthma control. However, there is little evidence available on the optimal timing, sequence, and degree of medication reductions. In this study we analyzed clinically stable asthmatic children who underwent a medication reduction from a combination preparation consisting of an inhaled corticosteroid (ICS) and long acting beta2-agonist (LABA) to monotherapy with the same dose of the ICS. We hypothesized that the extent of exercise-induced bronchoconstriction (EIB) would not increase after the cessation of the LABA. Nineteen children, aged 8-16 years, with clinically stable asthma, receiving LABA/ICS combination therapy, were analyzed in this open-label pilot study. Children performed an exercise challenge at baseline and 3 weeks after the medication reduction. Best values of spirometric measurements of the forced expiratory volume in 1 sec (FEV(1)) were used for statistical calculations. Maximum percent fall in FEV(1) was significantly lower after 3 weeks of ICS monotherapy (P = 0.03). Eight of 19 children had a >or=15% fall in FEV(1) after exercise at the initial exercise challenge. In this subgroup, maximum percent fall in FEV(1) after the medication reduction was significantly lower (P < 0.01), and in six children it decreased to <15%, indicating they no longer had EIB. In clinically stable asthmatic children on LABA/ICS combination therapy, the cessation of the LABA can reduce and in most cases abolish EIB.

Mannitol challenge for assessment of airway responsiveness, airway inflammation and inflammatory phenotype in asthma

Assessment of airway inflammation in asthma is becoming increasingly important, as the inflammatory phenotype underpins the treatment response. This study aimed to evaluate mannitol as a tool for assessing airway responsiveness and airway inflammation in asthma, compared with hypertonic saline. Fifty-five subjects with stable asthma completed a hypertonic (4.5%) saline challenge and a mannitol challenge at two separate visits, performed 48-72 h apart, in random order. Induced sputum was obtained from 49 (89%) subjects during the saline challenge and 42 (76%) subjects during the mannitol challenge (P>0.05). There was a significant correlation between the greatest percentage fall in forced expiratory volume in 1 s (FEV(1)) (r=0.6, P<0.0001), the dose-response slope (r=0.73), cumulative dose (r=0.55) and PD15 (r=0.46) for mannitol and hypertonic saline. The greatest percentage fall in FEV(1) to mannitol was less in non-eosinophilic asthma. There was a lower total cell count in mannitol vs. hypertonic-saline-induced sputum. However, sputum eosinophils and neutrophils were not significantly different. Using mannitol, a higher proportion of subjects were classified as having eosinophilic asthma. There were no differences in IL-8, neutrophil elastase or matrix-metalloproteinase 9 concentrations in sputum samples induced with mannitol or hypertonic saline. We conclude that mannitol can be used to induce good-quality sputum, useful for analysis of inflammatory mediators and for predicting the inflammatory phenotype in asthma.

O efeito da obesidade sobre parâmetros espirométricos em adolescentes submetidos à broncoprovocação por exercício

The effect of obesity on spirometric parameters in adolescents subjected to exercise bronchoprovocation. The objective of this study was to evaluate the effect of obesity on spirometric parameters in adolescents subjected to a physical exercise bronchoprovocation test. It was a cross-sectional, descriptive and correlational study composed of 15 adolescents of both genders. The diagnosis of asthma was made by clinical history and ISAAC questionnaire, and obesity by BMI above the 95 th percentile. The bronchoprovocation test with physical exercise was used for assessment of exercise induced asthma (EIA), considering positive a decrease in forced expiratory volume in one second (FEV1) > 10% of pre-exercise, and the intensity was calculated by the EIA maximum percentage fall in FEV1 (% Fallmax FEV1). We used the independent t test or Mann-Whitney U test and the Spearman rho correlation (p < 0.05). Significant differences were found between asthmatics and non-asthmatics to % Fallmax FEV1 (p = 0.034). There was a negative moderate relationship to Fallmax FEV1 with leukocytes, and % Fallmax FEV1 with leukocytes. It can be concluded that the spirometric variables presented moderated correlation with the systemic inflammation of obesity.

Exhaled nitric oxide and airway hyperresponsiveness in workers: a preliminary study in lifeguards

BackgroundAirway inflammation and airway hyperresponsiveness (AHR) are two characteristic features of asthma. Fractional exhaled nitric oxide (FENO) has shown good correlation with AHR in asthmatics. Less information is available about FENO as a marker of inflammation from work exposures. We thus examined the relation between FENO and AHR in lifeguards undergoing exposure to chloramines in indoor pools.Methods39 lifeguards at six indoor pools were given a respiratory health questionnaire, FENO measurements, spirometry, and a methacholine bronchial challenge (MBC) test. Subjects were labeled MBC+ if the forced expiratory volume (FEV1) fell by 20% or more. The normalized linear dose-response slope (NDRS) was calculated as the percentage fall in FEV1 at the last dose divided by the total dose given. The relation between MBC and FENO was assessed using logistic regression adjusting on confounding factors. The association between NDRS and log-transformed values of FENO was tested in a multiple linear regression model.ResultsThe prevalence of lifeguards MBC+ was 37.5%. In reactors, the median FENO was 18.9 ppb (90% of the predicted value) vs. 12.5 ppb (73% predicted) in non-reactors. FENO values ≥ 60% of predicted values were 80% sensitive and 42% specific to identify subjects MBC+. In the logistic regression model no other factor had an effect on MBC after adjusting for FENO. In the linear regression model, NDRS was significantly predicted by log FENO.ConclusionsIn lifeguards working in indoor swimming pools, elevated FENO levels are associated with increased airway responsiveness.